Method for manufacturing cellulose dipped articles



July 8, 1941. B. SCHACHTER METHOD FOR MANUFACTURING CELLULOSE DIPPED ARTICLES Filed Aug. 5, 1938 2 Sheets-Sheet 1 y 1941- B. SCHACHTER 2,248,253

METHOD FOR MANUFACTURING CELLULOSE DIPPED ARTICLES Filed Aug. 5, 1958 Y 2 Sheets-Sheet 2 wdm Q, INVENTOR.

ATTORNEY.

Patented July 8, 1941 UNITED STATES PATENT OFFICE METHOD FOR MANUFACTURING CELLULOSE DIPPED ARTICLES Benjamin Schachter, New York, N. Y.

Application August 5, 1938, Serial No. 223,221

2 Claims.

come by the control of solvent fumes discharged I by the cellulose coating and by providing means by which such control may be commercially effected. The forms may be of any desired shape enabling final removal therefrom of the finished cellulose article such as geometrical shapes including oblongs, squares, octagon and tubes,

closed at one end, and of any desired size as from /4" diameter to 20 inch diameter and from in length to 20" in length. Also, the thickness of the products may be varied in accordance with one phase of my invention which relates to a method of dipping.

The drawings accompanying this specification relate to apparatus for commercially controlling the solvent fumes after dipping. In the drawings:

Figure 1 is an end elevation of the fumecontrolling or drying apparatus, partly broken away to show therein a plurality of form-carrying, boards and the chambers which receive them.

Figure 2 is a longitudinal section on the line 2-2, Figure 1.

Figure 3 is a perspective view, showing one of the form-boards, and a carrier for dipping,

Figure 4 is a fragmentary side elevation, partly in section, of one of the form-boards, showing a coating of cellulose on each of a plurality of forms.

Figure 5 is a front elevation, partly in section,

showing the fume-control or drying apparatus, certain elements being in section for clearness of illustration.

Figure 6 is a view in elevation, partly in section, showing a modified form of suction assembly.

In practicing my invention]: provide a. pinrality of form-boards I, and, as shown in Figure 4, secure thereto forms 2 in spaced relation. These forms may be of glass, aluminum, or other smooth-surfaced material which is not affected by the acetone, diethyl phthalate or other solvent ingredients employed in making-the coating solution. Boards 1 may be of any desired size,

as, for example, 6- /2" x36" with a thickness of /3". The forms may be fixed to the boards or may be removably secured thereto.

When cellulose acetate is employed the solution mixture may be as follows:

Cellulose acetate 5 second viscosity pound 1 Santolite M 1'7 ounces 8 Diethyl phthalate do. 4 Acetone C. P do 22 190-proof S.'D. 1, alcohol do 10 Toluol do 4 Cellosolve acetate do 4 The above solution held in a tank, formed preferably with sliding covers, receives the form 1 preferably by means of a mechanical carrier which will hold the form-boards and will move them downwardly into the open top of the tank until the forms are covered by the solution. The tank may be of the constant level variety and in this dipping operation the flanges is: may straddle the walls of the tank so as not to come into contact with the solution. The forms should be 15 F. lower in temperature than the solution. Thus if the solution is room temperature (say, i'(l"-F.) the forms should be cooled to 55 F.

I have discovered that the thickness of the final article, i. e., the wall thickness, may be conthe timing is proportionately After the form-boards are withdrawn from the solution, they are turned with the coated forms end up and placed into the air-tight solventcontrol apparatus. The time of such control depends upon the thickness of the coating on the forms.

I will now describe the control apparatus:

Referring to the drawings, I have shown at 4 two frame members provided with bearings which receive the transverse shaft 5, each shaft carrying two flanged bearing wheels 5. The frame members support a third shaft 1 which carries a f-jrictional drive wheel 8, having a flanged periphery. Supported by the two sets of flanged wheels 6 is a drum comprising the side disk members'S, 9x, the latter being connected by an internal hub l0, the hub in the present embodiment, being octagonal in form, and eachwall of the octagon forms the base wall of a plural-cavity chamber, each cavity being adapted to receive a formits attached cellulose-coated forms.

exhaust pipe, and the two cavities of a chamber may have separate exhaust pipes, although in the .present embodiment I have shown a single ex-' haustpipe common to the two cavities of each chamber, the exhaust pipes being indicated at l and their control valves at I6, Figure 5. These u exhaust pipes lead to a solvent-vapor-receiving chamber l1 formed by a fixed cup-like wall I11: and a rotary cup-like wall Ham: to which the exhaust pipes are immediately secured. The'rctary cup-like member Ha: may be fixed to a carrier tube I8 having a hub I9 fixed to. drumwall 92:.

It will be seen from the above description that upon rotation of .the drum the exhaust pipes will partake of such rotation, and likewise, member lixa: of the collection chamber. Communicating with the interior of the collection cham-' her is an exhaust conduit which discharges into earth or other condensingmaterial for the solvent vapors. Below chamber 2! is a screen 22 and below the screen is a collection tank 23 for the condensed liquid, the latter being drawn off through valve-control pipe 24. In order to effect the exhaust action, I may employ a rotary pump 25 driven by motor 26, the pump having an intake pipe 21, leading upwardly within tank 23 and out of range of the descending condensate.

It will be underdstood that as the forms are dipped each form is placed within the cavity of one of the chambers and the cover for the cavity is closed. If the chamber was not revolved the solvent vapors, being twice the weight of air, would move to the base of each chamber and unequal drying would result. on the forms would tend to run downwardly. By revolving the chamber the vapors arenot only equalized, but the cellulose solution on the forms remains at uniform thickness.

The chamber-carrying drum is preferably revolved at the rate of 1 revolution per seconds continuously during the process, excepting when loading or unloading. Approximately 5 minutes onds. The exhaust is then shut ofi and 5 minutes thereafter the exhaust is repeated for a very short interval, say, approximately 1 second, and this is repeated every 5 minutes within the period 'of 25 minutes. Thereupon, a warm, dry

flush of air will be drawn into the cavities by 'the top ofa chamber 2| containing'infusorial Also, the solution after the forms are placed into the chambers, the

' vapors will have reached an approximate saturation point. This is a characteristic of my method. In other words, I enable the formation of an enveloping body of solvent vapors for the coated forms and thereby prevent too rapid drying of the outer surface of each coating. When the outer surface dries too fast, the solvent vapors in the undersurface are entrapped or unduly retarded in their movement, out of the coating. This develops pressures within the coating, thereby forming bubbles, corrugations and other deformities.

When the vapors have reached an approximate saturation point, a certain proportion of the vapors is exhausted. The power of theexhausting apparatus will be regulated in proportion to the size of the control drum and its chambers, the,

number of forms or objects dipped, and the thick- I ness of the coating on the dipped'forms.

thereafter the valve l6 or appropriate valves are opened and the exhaust is operated for 120 sec-;

opening the valve-control pipe H, for a few seconds, to complete drying. The articles may then be stripped from the forms. To strip the articles from the forms, they may be placed in hot water approximately 120 F., whereupon compressed air ejected through a nozzle may be applied along the sides of the forms which causes the articles to blow off instantly.

Thetiming is diflerent with different thicknesses of cellulose walls. Thus when the thickness is increased to 12 to 9 the solvent vapors, may be exhausted for 20 seconds at each of 4 times at '5 minute intervals. the exhausting operation may be effected every 5 minutes for. an interval of 1 second at a time and for 16 times. The valve-control pipe l4 may then be opened 'to enable flushing with roomtemperature air for a short period. For wall thickness above %0 slow exhaust timing is employed, a practical method being to start the exhaust of vapor after the coated forms have remained five minutes in their chamber cavities, the first exhaust period being 20 seconds and thereafter 1 exhaust period every 5 minutes for a time of 3 hours, followed by warm air flushing every 5 minutes for 4 .or 5 times, 1 second at a time.'

The timing also varies depending upon the thickness or viscosity of the solution. Some solutions may require movement of the form 1" in seconds for the first half of the, dipped object and 1" in 30 seconds for the balance. If the forms are redipped they are turned end up and placed 'in an airtight chamber and allowed to stand for a minute or so to equalize the coating on the form before the revolving action.

In Figure 6 the rotary pump is contained di-' rectly within the chamber formed by the cuplike walls l1, I-lara: and the fumes are discharged through a port 201: below which is the chamber 2L1: similar to chamber 2| and below which is collection.chamber 23.

Having described my invention, what I claim and desire to secure by Letters Patent, is as follows:

1. A method ofmanufacturing cellulose dipped articles,;"wliich comprises placing forms coated with cellulose solution in a'closedchamber until the evolved solvent vapors accumulate about the coatings, rotating the form during the evolution of the solvent vapors, and withdrawing the vapors by a plurality of vapor-exhausting steps, in the absence of the introduction of 'air into the closed chamber in said plurality of vapor exhausting steps.

2. A method of manufacturing cellulose dipped articles, which comprises placing a form coated with cellulose solution in a closed chamber until the evolved solvent vapors accumulate aboiit the coating, rotating the form during evolution of the solvent vapors, until the latter reach an approximate saturation point, then exhausting a proportion of the solvent vapors, continuing the said rotation, and withdrawing the remaining vapors by aplurality of vapor-exhausting steps Y spacedas to timing, in the absence of the intro- Thereafter, 

